The invention relates to a method of extracting fruit and vegetable juices, the fruit being reduced in order to produce mash, and the mash obtained from the reduced fruit being juiced.
A method of the above-mentioned type in which a naturally cloudy fruit or vegetable juice is to be obtained is known from European Patent Document EP 0 545 944 B1. According to this document, a mash obtained from reduced fruit is separated into flesh parts and juice in a solid-jacket screw-type centrifuge. The separation of insoluble fruit flesh parts by means of the solid-jacket screw-type centrifuge takes place immediately after the reduction of the fruit, and immediately thereafter, an inactivation takes place of pectolytic enzymes and polyphenol oxidases of the fruit by heating the juice draining out of the solid-jacket screw-type centrifuge.
As explicitly described in European Patent Document EP 0 545 944 B1, a mash is first obtained from the fruit by means of a grinding process. In a next process step, the mash is juiced (see FIG. 1). In this case, the physical structure of the mash plays an important role.
In addition to being extracted by means of solid-jacket screw-type centrifuges, juices can also be obtained by means of presses. The usable presses include discontinuously operating presses as well as belt and screw-type presses. For obtaining juice, screw-type presses are, however, used only to a limited extent. They are used more frequently in the field of the production of wine and fruit wine.
When obtaining juice, it is also possible to use full-liquefaction enzymes. In this case, the structure of the mash is impaired because, for reasons of taste, solids, such as stalks, cores and peels, are separated from the mash. This usually takes place by means of so-called finishers (for example, sieving machines; see FIG. 2). The structural impairment of the mash can at least largely be compensated by adding pressing aids (see FIG. 3). According to the state of the art, inorganic or organic substances are essentially used as pressing aids, which improve the physical structure of the mash. Rice husks, balm wood or perlites are used most frequently. However, these substances cause additional cost and therefore make the juice production more expensive. In addition, despite their partly natural origin, they represent a foreign substance, which is undesirable per se, in the respective natural fruit juice product.
Based on the above, it is an object of the invention to increase the quality of the mash when extracting fruit juice.
In contrast to the state of the art, according to the teaching of the present invention, peel components are added to another or a same mash before the juicing particularly after an optional separation of stalks and/or cores. This teaching is based on the idea of increasing the quality of the mash to be juiced by adding peel components. Peel components have no negative taste characteristics, but improve the structure of the mash. This applies essentially to any type of juicing.
According to a particularly preferred embodiment of the invention, the stalk, core and peel components are separated in a finisher from the mash obtained from the reduced fruit; then the peel components are separated from the remaining solids components and, before their juicing, are returned into the mash. This embodiment of the invention is also very suitable for a juice extraction in which enzymes or full liquefaction enzymes are used. In particular, the invention utilizes the recognition that, although for reasons of taste a separation of the stalks and cores from the mash is required, a separation of the peel components has no effect on the taste. The reason is that particularly the separation of the peel components results in a structural impairment of the mesh. This is prevented by returning the peel components. In contrast to the state of the art, it is even possible to eliminate the adding of other aids, which are not part of the fruit and cause additional costs.
The use of the invention for juicing by means of a solid-jacket screw-type centrifuge is particularly advantageous.
It is also particularly advantageous when peel components from the same mash or from another fruit mash occurring during another juicing are added to the mash to be juiced. Here also, it is particularly advantageous for the juicing to take place by means of a solid-jacket screw-type centrifuge.
It is also conceivable to intermediately store a portion of or all separated peel components and then add them to other fruit mashes. Thus, for example, when obtaining apple or pear juice, the peel components can be separated and then not be returned into the mash but, for obtaining a fruit juice from another type of fruit, be admixed to the mash made of this other type of fruit for improving the mash structure.
It is also conceivable to increase the fraction of peel components beyond the natural content of the original fruit and thereby improve the characteristics of the mashxe2x80x94for example, for obtaining a particularly high-quality and expensive juice.
It is also conceivable to optimize the effect of the peel components by a grindingxe2x80x94for example, finer or coarserxe2x80x94adapted to the characteristics of the original fruit.
It is also conceivable to subject the peel components to a thermal treatment before they are added to a mash. As a result, the structure of the peel components is strengthened and a durability is achieved simultaneously.
The separation of the peel components from the other solids can be carried out in a manner which is simple per se. Such a separation is known, for example, from the extraction of grape rape for producing grape seed oil. It therefore represents no technical difficulties to a person skilled in the art. However, a novelty of the present process is that, after the separation of the core and stalk components, the peel components are returned into the mash in order to improve its structure. The returning of the peels results in a clear improvement of the mash structure and therefore in an improved extraction of juice from the mash. Thus, full liquefaction as referred to above and in FIG. 3, can be utilized in the present invention without having to accept the disadvantage of impaired mash characteristicsxe2x80x94particularly the disadvantage of the poor juiceability of the mash.